Method of forming metal

ABSTRACT

A method and apparatus for forming metal wherein the method comprises the stops of moving finite lengths of metal along the prescribed path, stopping each length of metal at a predetermined position, moving a metal forming machine across the leading edge of the metal to form the same, moving the metal past the machine after it has cleared the metal, returning the machine to its initial position, reversing the movement of the metal along the path after it passes the machine to return it to a second predetermined position while moving a second piece of metal to the first predetermined position and repeating the moving of the machine across the trailing edge of the first piece of metal and leading edge of the second piece of metal to form the same and repeating the operation to form the leading and trailing ends of subsequently fed pieces of metal. The apparatus of the invention includes a first transfer table for moving the metal to the first predetermined position, a metal forming machine, means for moving the metal forming machine across the path of movement of the metal, and a second transfer table for moving the metal away from the machine and back toward the machine to the second predetermined position.

Jan. 23, 1973 United States Patent n91 Harris [54] METHOD OF FORMING METAL [57] ABSTRACT A method and apparatus for forming metal wherein Inventor: Robert A Harris, 1660 Clay Road,

Mableton, Ga. 30059 July 14, 1971 [22] Filed: the method comprises the stops of moving finite lengths of metal along the prescribed path, stopping each length of metal at a predetermined position, moving a metal forming machine across the leading edge of the metal to form the same 21 Appl.-No.: 162,630

, moving the metal Related [1.5. Application Data [62] Division of Ser. No. 818

,983, April 24, 1969, Pat. past the machine after it has cleared the metal, return- No. 3,610,017. ing the machine to its initial position, reversing the movement of the metal along the path after it passes the machine to return it to a second predetermined position while moving a second piece of metal to the first predetermined position and repeating the moving of the machine across the trailing edge of the first piece of metal and leading edge of the second piece of References Cited metal to form the same and repeating the operation to UNITED STATES PATENTS form the leading and trailing ends of subsequently fed .pieces of metal. The apparatus of the invention includes a first transfer table for moving the metal to the first predetermined position, a metal forming machine, means for moving the metal forming machine across 1 a t e l l a H r e .l. e e in W the path of movement of the metal, and a second transfer table for moving the metal away from the machine and back toward the machine to the second predetermined position.

Primary Examiner-Charles W. Lanham Assistant Examiner-Michael J. Keenan Attorney-B. J. Powell 5 Claims, 7 Drawing Figures METHOD OF FORMING METAL CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional application of my copending application Ser. No. 818,983, filed Apr. 24, 1969, now U. S. Pat. No. 3,610,017.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the forming of metal and more particularly to forming the leading and trailing edges of pieces of metal by holding the pieces of metal stationary while a forming machine is moved across the leading and trailing edges thereof to form the same.

2. Discussion or the Prior Art In the past, metal, especially sheet metal, was first cut to length from a roll and subsequently hand fed to a roll forming machine to form the leading and trailing edges of the sheet metal to form locking grooves and reinforcing angles in the metal. While machines were available on the market to rapidly cut the sheet metal to lengths, the overall operation of cutting and forming the metal was very time consuming in that the manually fed forming machines were slow. Recently, there has been an attempt to manufacture a machine which would cut the sheet metal to lengths and subsequently form the same in a single overall operation without the sheet metal being manually fed through the roll forming machine. All of these machines have attempted to solve this problem by using a complicated transfer system to change the position of the sheet metal several times and subsequently feed the sheet metal through two separate forming machines either sequentially or simultaneously to form the locking and reinforcing bends therein. In these machines, the forming machine is always stationary and the metal is moved thereby.

SUMMARY OF THE INVENTION These and other problems associated with the prior art are overcome by the invention disclosed herein in that metal, especially sheet metal, can be rapidly cut to length and subsequently formed in a single overall operation with a minimum of transfer equipment and using a single roll forming machine. This not only substantially reduces the initial cost of the equipment, but also provides a fast and efficiently operating machine with a minimum of moving parts thereby reducing the overall maintenance cost of the machine.

The method of the invention comprises the steps of moving pieces of sheet metal successively along a prescribed path, stopping each piece of metal at a predetermined position and moving a metal forming machine across the loading edge thereof, subsequently moving the formed piece of metal past the machine, returning the machine' to its original position, then moving the formed sheet of metal back to a second predetermined position and moving the next unformed sheet of material to the first predetermined position, and moving the machine across the trialing edge of the formed piece of material and the leading edge of the unformed piece of material to form the same. This operation is repeated on successive pieces of metal.

The apparatus of the invention includes generally an infeed transfer table from moving the pieces of metal to the first predetermined position, a metal forming machine mounted on a traversing mechanism to move the machine back and forth across the path of the pieces of metal and a discharge transfer table for moving the pieces of metal away from the forming machine and back toward the forming machine to the second predetermined position.

BRIEF DESCRIPTION OF THE DRAWINGS These and other features and advantages of the invention disclosed herein will become more apparent upon consideration of the following specification and accompanying drawings wherein like characters of reference designate corresponding parts throughout the several views and in which:

FIG. 1 is a partial perspective view of one embodiment of the invention;

FIG. 2 is a top plan view of the invention shown in FIG. 1;

FIG. 3 is a shortened side elevational view of the discharge transfer table of the invention shown in FIGS. 1 and 2 with parts thereof broken away to show the internal construction thereof;

FIG. 4 is a partial view showing the drive mechanism for the discharge table;

FIG. 5 is a partial sectional view showing the braking mechanism of the machine;

FIG. 6 is an electrical schematic diagram of the control circuit of the invention; and,

FIG. 7 is a schematic diagram of the fluid control circuit of the invention.

These figures and the following detailed description disclose specific embodiments of the invention; however, the inventive concept is not limited thereto since it may be embodied in other forms.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS Referring to FIG. 1, it will be seen that the invention includes generally an infeed transfer table 10, a discharge transfer table 11, a metal forming assembly 12, and a traversing mechanism 14. The infeed transfer table 10 and the discharge transfer table 11 are aligned so that they will move pieces of metal, here shown as sheet metal M, along a common prescribed path P shown in FIG. 1. The traversing mechanism 14 mounts the metal forming assembly 12 and is sufficient to move the metal forming assembly back and forth across the path P. For sake of clarity, the machine will be divided up into the components above listed with sub-headings. Traversing Mechanism The traversing mechanism 14 includes a frame 15 defined by parallel side members 16 and end members 18. Each side member 16 mounts a carriage rail 19 thereon, the carriage rails 19 being L-shaped in crosssection and positioned so that they are opposed to each other. The rails 19 are also oriented parallel to each other while substantially perpendicular to the path P and spaced there below. A starting fluid cylinder 20 is mounted on one of the end members 18 (the near side of the machine as seen in FIG. I) and has as its piston rod 21 selectively extendable toward the path P. A pusher plate 22 is provided on the end of piston rod 21 to start the metal forming assembly 12 moving toward the path P as will be explained hereinafter. A return fluid cylinder 24 is mounted on the end member 18 opposite the starting fluid cylinder 20 and has its piston rod 25 extending toward the path P. A pusher plate 26 is provided on the extending end of piston rod 25 to return the metal forming assembly 12 back across path P, to its initial position. Each end member 18 pivotally mounts a pair of braking members 28 as seen in FIGS. 1 and with each braking member 28 extending inwardly within the frame toward the path P and provided with an angle portion 29 which extends below the lower surface of metal forming assembly 12. Each braking member 28 is urged upwardly toward a substantially horizontal position by a spring 30. The braking members 28 serve to slow down the movement of the metal forming assembly 12 as it approaches each end of the frame 15 to prevent injury to the cylinders and 24. Metal Forming Assembly The metal forming assembly 12 is carried by the carriage rails 19 of the traversing mechanism 14. The metal forming assembly 12 includes a roll-type metal forming machine 31 which is conventional in construction and which forms various types of flanges and locking grooves in sheet metal work. Such a machine is manufactured by The Lockformer Co., 4615 W. Roosevelt Rd., Chicago, Illinois 60650. It is to be understood, however, that different type forming machines may be used in the metal forming assembly 12. The particular metal forming machine 31 shown includes a plurality of forming rolls (not shown) mounted in the roll housing 32 on top of the machine which engage the edges of sheet metal and roll the same into the desired configuration. Normally the rolls engage the metal and feed the metal with respect to the machine, however, the metal is stationary in this application and the rolls in the housing 32 engage the metal and propel the metal forming machine 31 along the carriage rails 19. The machine 31 is mounted on casters 34 which support the machine on the rails 19 and allow the machine to be easily rolled back and forth along the carriage rails 19.

Added to this conventional metal forming machine 31 is an extension table 35 which is in the plane of the table 36 of the forming machine 31 and which extends just under the path P along which the metal M moves when the metal forming assembly 12 is adjacent-the starting fluid cylinder 20 as seen in FIG. 1. A pair of guide arms 38 and 39 extend from the roll housing 32 along the top of the extension table 35 into the path P along which the metal M travels. As the metal M moves along the path P it is first engaged by the guide arm 38 and held in position for forming by the machine 31. As the metal M moves past the machine along the path P and then back toward the machine along the path P, the trailing edge of the metal M engages the guide arm 39 and positions it properly for engagement by the rolls of the forming machine 31. The extension table 35 serves to support the metal M prior to engagement by the machine 31.

A by-pass extension table 40 is provided at the end of the machine 31 opposite the table 35 and in the same plane therewith. The table 40 supports the metal M when the machine 31 has moved to the far end of the traversing mechanism 14 and the metal M is moved from the infeed transfer table 10 to the discharge transfer table 11. The table 40 defines openings 41 therethrough through which by-pass rolls 42 extend to power the metal M from the table 10 to the table 11. The rolls 42 are driven by a motor 44 connected to the rolls 42 by a belt drive 45. The rolls 42 are driven so that metal M will be moved across the table 40 from the right to the left as seen in FIG. 1. A set of freely rotatable hold-down rolls 46 are positioned above the table 40 over the rolls 42 to maintain driving contact between the metal M and rolls 42. The rolls 46 are urged toward rolls 42 by springs 48. Infeed Transfer Table The infeed transfer table 10 is positioned adjacent the traversing mechanism 14 as seen in FIG. 1 on the right side thereof. It is substantially centered along the length of the mechanism 14 perpendicular thereto and the path of travel of the assembly 12 is of sufficient length for the metal to clear the roll housing 32 when the assembly 12 is in its initial position and when the assembly 12 is in its traversed position. The table 10 comprises a frame 49 which rotatably mounts a plurality of axially aligned, laterally spaced rollers 50 at each end thereof. The rollers 50 mount endless belts 51 therearound in a position such that the upper flights of the belts 51 are in the plane of the extension tables 35 and 40 of the assembly 12. The belts 51 are moved continuously in the direction shown by arrows 52 by a conventional drive mechanism 53 (see FIG. 6). The metal M that has been cut to length is fed to the table 10 which in turn moves the metal M toward the guide arm 38. The speed of the belts 51 can be varied to move the metal M toward the guide arm 38 at the desired speed.

Positioned along that edge of the frame 49 facing the assembly 12 is a pair of laterally spaced hold-down fluid cylinders 54. The piston rods 55 of the cylinders 54 extend downwardly and have rubber pads 56 on the depending end of each. When fluid is supplied to the cylinders 54, the rods 55 thereof force the pads 56 down against the frame 49. If the metal M is between the frame 10 and pads 56, it will be locked in position, but if the metal M is not between the frame 10 and pads 56, the pads 56 will block the movement of metal M into the space through which the machine 31 passes. This operation will be more fully explained hereinafter. Discharge Transfer Table The discharge transfer table 11 is positioned adjacent the left side of the traversing mechanism 14 as seen in FIG. 1. It is substantially centered along the length of the mechanism 14 in alignment with the table 10 so that the table 10 and table 11 move each piece of metal M along the common path P. The discharge transfer table 11 includes a frame 58 having legs 59 as seen in FIG. 3 which support the same. A pair of spaced parallel side members 60 extend between legs 59 and a pair of spaced parallel end members 61 join the legs 59 and side members 60 to define an open retangular shape. Spaced intermediate members 62 connect the end members 61 and are parallel to side members 60.

Rotatably mounted between the side and intermediate members 60 and 62 are a plurality of rolls 64 which are spaced back from the entry end of the frame 58 and are mounted on a common shaft 65. The shaft 65 is journalled in bearing blocks 66 in FIGS. 3 and 5 carried by intermediate members 62. A plurality of rolls 68 are rotatably mounted between the side and intermediate members 60 and 62 as seen in FIGS. 2 and 4 on a common shaft 69 journalled in bearing blocks 70 adjacent the exit end of frame 58. The rolls 64 and 68 mount endless return belts 71 therebetween. The shaft 65 is driven by a conventional driving mechanism 72 so that the upper flights of belts 7] lie in the same plane as the upper flights of the belts 51 and move toward the assembly 12 as shown by arrows 73 in FIGS. 1 and 2.

A plurality of driving discharge rolls 74 are rotatably carried between the rolls 64 and spaced adjacent the entry end of the frame 58. The rolls 74 are mounted on a common shaft 75 parallel to the shaft 65 and spaced therefrom. The shaft 75 is journalled in bearing blocks 76 mounted on pivot links 78 which are pivotally mounted on the shaft 65. A spur gear 79 is mounted on shaft 65 and a pinion 80 is mounted on shaft 75 in mesh with gear 79. Therefore, it will be seen that the gear 79 will drive shaft 75 as shaft 65 is rotated by mechanism 72. The links 78 can be pivoted about shaft 65 to vary the vertical position of shaft 75 as seen in FIG. 4.

A plurality of driven discharge rolls 81 are mounted on a common shaft 82 inwardly of the exit end of the frame 58. The shaft 82 is journalled in bearings 84 carried by side members 60 and positions the uppermost surface of the rolls 81 in substantially the same horizontal plane as the uppermost surface of rolls 68. The rolls 74 and 81 mount endless belts 85 therebetween so that as the rolls 74 are moved up and down by pivoting the links 78, the upper flights of belts 85 will move above and below the upper flights of the belts 71 as seen in FIGS. 3 and 4. The gear 79 and pinion 80 serve to move the belts 85 away from the assembly 12 as shown by arrows 86 in FIGS. 1 and 2. The gear 79 and pinion 80 are so constructed that the belts 85 are moved faster than the belts 71 to insure that the metal M will clear the assembly 12. The arrangement shown moves the belts 85 three times faster than belts 71.

A vertically movable support member 88 is positioned under the upper flight of each of the belts 85. The members 88 are carried by a tranversely extending sub-carriage 89 at each end thereof. Each of the subcarriages 89 is carried by the piston rods 90 ofa pair of spaced fluid cylinders 91. The fluid cylinders 91 are mounted on carriage beams 92 extending between legs 59 of frame 58 below the side, end and intermediate members 60, 61 and 62. When the piston rods 90 are extended, the upper flights of belts 85 will be positioned above the plane of the upper flights of belts 71 and when they are retracted, the upper flights of belts 85 will be below the plane of the upper flights of belts 71. In this manner, the belts 85 are used to discharge the formed metal M and the belts 71 are used to return the partially formed metal M back toward the guide arm 39.

The extending end of each link 78 is pinned to the piston rod 94 of a fluid cylinder 95 carried by the carriage beams 92. When the piston rods 94 are extended, the uppermost surfaces of rolls 74 are above the uppermost surfaces of rolls 64 so that the belts 85 are also above the belts 71 at the right ends thereof as seen in FIG. 3. This also serves to reduce the tension in the belts 85 so that the members 88 can be raised by cylin-' ders 91. When the piston rods 94 are retracted, the right ends of belts 85 are below the belts 71 as seen in FIG. 4. The operation of these various components is set forth hereinafter.

A pair of hold-down fluid cylinders 96 are carried by the frame 58 adjacent the assembly 12 and correspond in construction and function to the hold-down cylinders 54 of the table 10. Each cylinder 96 has a piston rod 98 with a pad 99 on the depending end thereof. As the piston rods 98 are extended, the pads 99 will move toward end member 61 as seen in FIG. 3 to clamp metal M therebetween or prevent metal M from moving back into the path of the assembly 12.

CONTROL CIRCUIT The electrical control circuit U is shown schematically in FIG. 6 and the various switches as well as their function are listed in the table below:

Switch SW-1 Function Closed when leading edge of metal in first predetermined position and serves, in conjunction with SW-2 to move the forming machine into contact with the metal.

Closed when trailing edge of metal in second predetermined position and serves, in conjunction with SW-l, to move the forming machine into contact with the metal.

Opened when metal is crossing bypass extension table and serves, in conjunction with SW-4 and SW-9, to prevent return of forming machine when metal interferes with its movement.

Opened when metal on infeed table interferes with return of forming machine and serves, in conjunction with SW-3 and SW-9, to prevent return of forming machine when metal interferes with its movement.

Closed when forming machine has passed across metal to raise discharge belts into engagement with metal on discharge table.

Closed as forming machine starts across metal to activate cam to control Sw9.

Closed as forming machine moves across traversing mechanism and activates holddown fluid cylinders on infeed and discharge transfer tables.

Closed as forming machine moves across traversing mechanism and activates holddown fluid cylinders on infeed and discharge transfer tables.

Closed when forming machine in traversed position and serves, in conjunction with SW-3 and SW-4 to return forming machine to its initial position.

Manually closed to by-pass SW-2 to start operation with one piece of metal.

The control circuit U includes a hot wire 100 and a ground wire 101. Switches SW-l SW-2, SW-S, SW-7, SW-S, and Sw-9 are normally open cam operated switches of conventional construction while switches SW-3 and SW-4 are normally closed cam operated switches. Switch SW-6 is a two position toggle switch of conventional construction and will remain in either position. Switch SW-l0 is a normally open push button switch of conventional construction.

Switches SW-1 and SW-2 in series with solenoid SOL-1 connect wires 100 and 101. Switch SW-10 is connected across switch SW-2 in parallel therewith. Switches SW-3, SW-4, and SW-9 in series with solenoid SOL-2 connect wires 100 and 101. Switches SW-7 and SW-8 in parallel with each other and in series with solenoid SOL-3 also connect wires 100 and 101. Switch SW-S in series with solenoid SOL-4 connects wires 100 and 101 while switch SW-6 in series with solenoid SOL- connects the wires 100 and 101 also. The drive motor of mechanism 53 is connected between wires 100 and 101 in series with a variable speed controller 102, and the drive motor of mechanism 72 is connected between wires 100 and 101 in series with a variable speed controller 104.

The switch SW-l is located on the extension table 35 in the guide arm 38 so that it will be activated when the metal M engages the arm 38. The switch SW-2 is located on the extension table 35 in the guide arm 39 so that when the metal M engages the guide arm 39, the switch SW-2 will be activated. The switch SW-3 is located in the by-pass extension table 40 so that it will be activated when the metal is on the extension table 40. The switch SW-4 is located on the exit end of the infeed transfer table so that it will be activated by the metal M while it is protruding into the path of the assembly 12.

The switch SW-S is located on the entry end of the discharge table 11 so that it is activated by the assembly 12 when the assembly has traversed the mechanism 14 and cleared the metal M. The switch SW-6 is located on the side of the assembly 12, and is closed as the assembly 12 traverses the mechanism 14 and is opened when the assembly 12 is returned. Switch SW-7 is located on the exit end of the infeed transfer table 10 adjacent the assembly 12 in its initial position and is activated by a cam 105 as seen in FIG. 1 when the assembly 12 is starting its traversing movement or is completing its return movement. The switch SW-8 is located on the exit end of the infeed transfer table in alignment with switch SW-7 but on the opposite side of the table 10 and is activated by cam 105 as the assembly 12 is completing its traversing movement and is starting its return movement.

Switch SW-9 is located on the entry end of the discharge transfer table 11 and is activated by an appropriate cam (not shown) on the assembly 12 as it reaches the traversed position. Switch SW-l0 is located on an appropriate control panel (not shown) and is manually activated.

FIG. 6 is a schematic diagram of the hydraulic control circuit H. The circuit H shows the cylinders 54 and 96 in parallel connected to the manifold M built into the frames 49 and 58 through valve V3 activated by solenoid SOL-3. Cylinders 91 and 95 are in parallel with each other and connected to the manifold M through valve V4 activated by solenoid SOL-4. Cylinder is connected to manifold M through valve V1 activated by solenoid SOL-l and cylinder 24 is connected to manifold M through valve V2 activated by solenoid SO L-2. The cylinders 54,91, 94 and 96 are of the conventional retracting type when pressure is not applied thereto. It is to be understood that different types of components may be used in the circuits U and H from those shown without departing from the scope of the invention.

OPERATION In operation, it will be seen that the invention is set up for operation by appropriately adjusting the speed of the belts 51, 71 and 85 by manipulating the controllers 102 and 104. A piece of sheet metal M is cut to length and deposited on the belts 51 of the infeed transfer table 10. The belts 51 move the piece of metal M along the path P until the leading edge of the metal M engages the guide arm 38. The metal M is in its first predetermined position and has closed switch SW-l and opened switch SW-4. The switch SW-10 is closed manually to short out switch SW-2. This energizes solenoid SOL-1 to activate valve V1 and supply fluid from a pressure source (not shown) through manifold M to cylinder 20 and extends piston rod 21. This moves the assembly 12 sufficiently far toward the metal M for the rolls in the housing 32 to engage the leading edge of the metal M.

Since the machine 31 is constantly energized, the rolls in housing 32 engage the metal M and move the machine 31 across the leading edge of the metal while forming the same. At about the time the rolls engage the metal M, the cam 105 closes switch SW-7 to energize solenoid SOL-3. This causes valve V3 to admit fluid under pressure from manifold M to cylinders 54 and 96 to extend piston rods 55 and 98 to clamp the metal M in position.

As the machine 31 continues to move across the metal M by the rolls in housing 32, the cam 105 eventually engages switch SW-8 to maintain the piston rods 55 and 98 extended. The cam 105 may be so constructed that switch SW-7 is opened momentarily before switch SW-S is closed. This allows the metal M to be released momentarily so that the rolls in the housing 32 may realign the metal M with respect thereto. The alignment function is inherent in the operation of the machine 31.

When the rolls in housing 32 clear the leading edge of the metal M, there is enough momentum in the machine 31 to carry it to its full traversed position to be engaged by braking members 28 and its movement arrested. In this position, the metal M can pass the roll housing 30 across the by-pass extension table 40. As the assembly 12 reaches its traversed position, cam 105 releases switch SW-8 thereby allowing it to open and release the metal M. Switch SW-6 has already been tripped to its closed position by an appropriate cam (not shown) so that solenoid SOL-5 is energized and the cam (not shown) that operates switch SW-9 is extended to close switch SW-9 when the assembly 12 is in its traversed position. Switch SW-S is also closed by an appropriate cam (not shown) on the assembly 12 when in its traversed position. This energizes valve V4 to extend piston rods and 94 of cylinders 91 and 95 and raise discharge belts 85 above return belts 71.

The piece of metal M that has its leading edge formed is then moved across table 40 by belts 51 of the infeed transfer table 10 and the continuously operating rolls 42 in table 40 and onto the raised belts 85 of the discharge transfer table 11. The belts 85 then move the metal M with its leading edge formed along the path P away from the assembly 12.

As soon as the metal M clears switches SW-3 and SW-4, solenoid SOL-2 is energized as switches SW-3 and SW-4 close since switch SW-9 is already closed. This causes valve V2 to extend piston rod 25 of cylinder 24 to return the assembly 12 back to its original position. As soon as the assembly 12 starts its return movement, switches SW-S are opened to lower the discharge belts 85 below the belts 71 so that the metal M having its leading edge formed is dropped on belts 71 and starts back toward the assembly 12. Switch SW-9 is also opened when the assembly 12 leaves its traversed position to remove the pressure from cylinder 24. Switches SW-7 and SW-8 are closed by cam 105 as the assembly 12 is returning in reverse order from that set forth on the traversing movement so that the pads 56 and 99 prevent metal M from entering into interference with the returnof assembly 12. As the assembly 12 approaches its initial position, the switch SW-6 is tripped to its open position to retract is associated cam (not shown).

While the assembly 12 is returning, another piece of metal M is being moved along the path P by the infeed transfer table and the piece of metal M on the discharge transfer table is being returned along the path P toward assembly 12. When the assembly 12 is returned to its initial position, cam 105 clears switches SW-7 and SW8 so that piston rods 55 and 98 of hold down cylinders 54 and 96 are retracted. This allows the table 10 to move the leading edge of the second piece of metal M against the guide arm 38 to its first predetermined position and the table 11 to move the trailing edge of the first piece of metal M back against the guide arm 39 to its second predetermined position. These positions are shown by dotted lines in FIG. 2. In these positions switch SW-1 is closed by the leading edge of the second piece of metal M and the switch SW-2 is closed by the trailing edge of the first piece of metal M. This activates cylinder to move the rolls in housing 32 into engagement with the leading edge of the second piece of metal and the trailing edge of the first piece of metal.

The rolls in housing 32 move the assembly 12 to its traversed position as set forth above to form both the leading and trailing edges. This time, however, the cylinders 96 also clamp the first piece of metal M in position. At the end of the traverse movement of the assembly 12, the discharge belts are raised and moves the first piece of metal M from the table 11 and moves the second piece of metal M into the position of the first piece on the table 11. The operation continues as more pieces of metal are fed to table 10.

The speed of belts 51, 71 and 85 are adjusted to present new pieces of metal to the assembly 12 at the appropriate intervals and to discharge each piece of metal having both leading and trailing edges formed from the table 11 but keep the metal with only the leading edge formed on the table 11.

It is to be understood that the use of modifications, substitutions, and equivalents may be used without departing from the scope of this invention.

lclaim:

1. A method of forming opposite edges of a piece of metal with a metal forming machine comprising the steps of:

a. moving the piece of metal along a prescribed path toward a first predetermined position;

b. stopping the piece of metal at said first predetermined position;

c. moving the metal forming machine into operative engagement with one edge of the piece of metal and then across the edge to form same;

d. after the metal forming machine has moved past the edge of the piece of metal, moving the metal along said path past the forming machine so that the opposite edge of the metal is facing the machine;

e. moving the metal forming machine back to its initial position after the piece of metal has passed the machine;

f. reversing the movement of the piece of metal and moving the opposite edge of the metal back toward the forming machine to a second position;

g. stopping the piece of metal at the second position;

and,

. moving the metal forming machine into operative engagement with the opposite edge of the piece of metal from the edge already formed and then across the opposite edge to form the same.

2. The method of claim 1 wherein said piece of metal is sheet metal, said one edge is the leading edge of said sheet metal as it moves along said predetermined path, and said opposite edge of said sheet metal is the trailing edge as it moves along said prescribed path.

3. The method of claim 2 further including moving a second piece of sheet metal into said first predetermined position when the first piece of sheet metal is in said second predetermined position and before step (h) so that said metal forming machine is also moved into operative engagement with said second piece of sheet metal during step (h) to form the leading edge of said second piece of sheet metal simultaneously with the forming of the trailing edge of said first-piece of sheet metal.

4. The method of claim 3 further including the steps of moving said first piece of sheet metal away from said machine, moving said second piece of sheet metal to the position of said first piece of sheet metal in step (g) after step (h), moving another piece of sheet metal to the position of said first piece of sheet metal in step (b), and repeating the steps as additional pieces of sheet metal are moved along said prescribed path.

5. A method of forming opposite edges of finite lengths of sheet metal with a metal forming machine comprising the steps of:

a. moving a first finite length of sheet metal along a prescribed path toward a first predetermined position;

. stopping said first length of sheet metal at said first predetermined position;

. moving the machine into operative engagement with the leading edge of said first length of sheet metal and moving the machine across the leading edge of the sheet metal to form the leading edge;

. after the machine has moved past the leading edge of said first length of sheet metal, moving said sheet metal along said path until the trailing edge of said sheet metal is past said machine;

e. returning the machine back to its original position after said first length of sheet metal has passed said machine;

f. reversing the movement of said first length of sheet metal to move the trailing edge thereof back toward said machine to a second predetermined position;

g. moving a second finite length of sheet metal along said prescribed path to the position set forth in P0 repeating step (c) to form the trailing edge of said first length of sheet metal and the leading edge of said second length of sheet metal; and,

. continuing the above steps to form both the leading and trailing edges of each length of successively fed length of sheet metal.

a: a: i 

1. A method of forming opposite edges of a piece of metal with a metal forming machine comprising the steps of: a. moving the piece of metal along a prescribed path toward a first predetermined position; b. stopping the piece of metal at said first predetermined position; c. moving the metal forming machine into operative engagement with one edge of the piece of metal and then across the edge to form same; d. after the metal forming machine has moved past the edge of the piece of metal, moving the metal along said path past the forming machine so that the opposite edge of the metal is facing the machine; e. moving the metal forming machine back to its initial position after the piece of metal has passed the machine; f. reversing the movement of the piece of metal and moving the opposite edge of the metal back toward the forming machine to a second posItion; g. stopping the piece of metal at the second position; and, h. moving the metal forming machine into operative engagement with the opposite edge of the piece of metal from the edge already formed and then across the opposite edge to form the same.
 2. The method of claim 1 wherein said piece of metal is sheet metal, said one edge is the leading edge of said sheet metal as it moves along said predetermined path, and said opposite edge of said sheet metal is the trailing edge as it moves along said prescribed path.
 3. The method of claim 2 further including moving a second piece of sheet metal into said first predetermined position when the first piece of sheet metal is in said second predetermined position and before step (h) so that said metal forming machine is also moved into operative engagement with said second piece of sheet metal during step (h) to form the leading edge of said second piece of sheet metal simultaneously with the forming of the trailing edge of said first piece of sheet metal.
 4. The method of claim 3 further including the steps of moving said first piece of sheet metal away from said machine, moving said second piece of sheet metal to the position of said first piece of sheet metal in step (g) after step (h), moving another piece of sheet metal to the position of said first piece of sheet metal in step (b), and repeating the steps as additional pieces of sheet metal are moved along said prescribed path.
 5. A method of forming opposite edges of finite lengths of sheet metal with a metal forming machine comprising the steps of: a. moving a first finite length of sheet metal along a prescribed path toward a first predetermined position; b. stopping said first length of sheet metal at said first predetermined position; c. moving the machine into operative engagement with the leading edge of said first length of sheet metal and moving the machine across the leading edge of the sheet metal to form the leading edge; d. after the machine has moved past the leading edge of said first length of sheet metal, moving said sheet metal along said path until the trailing edge of said sheet metal is past said machine; e. returning the machine back to its original position after said first length of sheet metal has passed said machine; f. reversing the movement of said first length of sheet metal to move the trailing edge thereof back toward said machine to a second predetermined position; g. moving a second finite length of sheet metal along said prescribed path to the position set forth in step(h); h. repeating step (c) to form the trailing edge of said first length of sheet metal and the leading edge of said second length of sheet metal; and, i. continuing the above steps to form both the leading and trailing edges of each length of successively fed length of sheet metal. 